Apparatus for screening liquid



Aug 28 1956 o. G. NELSON 2,760,644

APPARATUS Foa SCREENING LIQUm Filed April 5. 1954 INVENTOR OSCAR G. NELSON 7W@ vw ATTORNEYS nited States Patent O APPARATUS FOR SCREENING LIQUID Oscar G. Nelson, Costa Mesa, Calif., assignor to Turco Products, Inc., Los Angeles, Calif., a corporation of California Application April 5, 1954, Serial No. 421,133

1 Claim. (Cl. 210-149) This invention has to do with apparatus for use in pumping a solvent or cleaning solution through a tank or other container to be cleaned or from which a coating must be stripped and particularly with apparatus of this type providing storage capacity, a pump, and means for straining and recirculating returned solution.

While the present apparatus may have many uses it is particularly designed for the circulation and recirculation of solvent solutions in the removal of so-called sealant lining the walls of the integral fuel tanks in the wings of large, modern aircraft. Sealant is a term employed to designate the sealing compounds used to line such fuel tanks. Examples of sealants are: zinc chromate paste, accelerator-cured Thiokol, water dispersion Thiokol, and Buna N synthetic rubber.

Sealants have a limited life and after several thousand flying hours are required to be removed. A common way of doing this at present is to spray a suitable solvent against walls of the tank, draining off the solvent and removed sealant and recirculating the solvent until all the sealant has been removed. It is necessary to strain the liquid draining from the tanks to remove solids from the liquid before recirculating it.

An object of the present invention is to provide novel, portable apparatus for storing and pumping a liquid such as a solvent solution used in the removing of sealant from interiors of integral fuel tanks of aircraft, for receiving and straining returned liquid, and for repumping returned liquid.

Another object of the invention is to provide novel apparatus of the type indicated for straining liquid returned to the apparatus which embodies a novel arrangement of removable screen umts.

More particularly it is an object to provide a novel arrangement of screening devices for use in a tank or the like.

Still another object of the invention is to provide novel means for facilitating operation of the screen units by preventing clogging thereof.

These and other objects will be apparent from the drawing and the following description.

Referring to the drawing, which is illustrative of a preferred form of the invention:

Fig. l is a side elevational view of apparatus embodying the invention;

Fig. 2 is a plan View, partly broken away, of the apparatus of Fig. l;

Fig. 3 is an enlarged Vsectional view on line 3--3 of Fig. 2;

Fig. 4 is a sectional view on line 4--4 of Fig. 3; and

Fig. 5 is an enlarged sectional view of the upper righthand portion of Fig. 4.

More particularly describing the invention, 11 generally indicates a trailer-type vehicle or truck provided with container or storage means 12 for liquid. This includes a large, open-topped tank 14 and a somewhat smaller tank 15. The latter is primarily for the purpose of holding a concentrate or for the mixing of a required so- Patented Aug. 28, 1956 'ice lution. The large tank, 14, is used as a storage means for the solution being circulated. The tank 14 is provided with two openings 16 in the upper wall 18 thereof, these being defined by vertical walls 20. Removable covers 23 serve to close the openings.

Mounted on the vehicle is a pump 24, driven by a motor 25. A main intake conduit 27 leads from the bottom of the large tank 14 to the pump. A second pump intake conduit 28 leads from tank 15. A pressure or delivery conduit 30 is connected to the exhaust side of the pump and extends to the rear of the vehicle where it terminates in a header 32. A plurality branch delivery or outflow pipes 33 connect with the header and have valves 34.

Return pipes 36 having valves 37 are mounted on and communicate with a return header 39. The latter has a single outlet 41 which extends through the rear wall 42 of the tank means 12 to the interior of tank 14.

In the operation of the apparatus, the required solution is pumped from tank 14 through conduits 27 and 30 and out through one or more hoses H as may be connected to the delivery pipes 33. This solution is ordinarily sprayed against the walls of the fuel tanks to be cleaned by spray devices temporarily mounted on the tanks. The liquid drains from the fuel tanks and is returned to tank 14 through one or more hoses H' connected to return pipes 36. The returning solution carries dissolved and partially dissolved sealant and it is necessary to strain all solids from lthe returned solution before recirculating it. I accomplish this by means of the screen units 45 and 46. These are shown as open-topped containers having a metal frame 47 with sides and bottoms of wire mesh or screening 4S. The screen units are suspended in the tank 14 by means of hangers 49 on the frame 47 having U-shaped upper ends 50 which t over the upright walls defining the openings 16. The screen units are preferably rectangular and of a dimension such that they are removable through the openings 16.

The screen unit 45, which will be termed the main screen unit, is larger than the other unit and extends substantially the full height of the tank. The unit 46 or auxiliary unit is considerably shorter, the bottom being disposed a substantial distance above the floor of the tank and the top being disposed substantially below the top of the tank.

The side of the screen unit 45 adjacent the other screen unit terminates somewhat short of the top at 51 to provide an overflow path down an apron 52 which overhangs the screen unit 46.

One of the features of my invention is the provision of means for preventing clogging of the screen units and this comprises a pipe 56 connected to pipe 30 and having a plurality of discharge openings 58 therealong shown as arranged in two rows. The pipe is controlled by a valve 57. The openings in the pipe face toward the screen units 45 and 46 so as to direct liquid issuing therefrom against the side of the screen units. During operation of the apparatus, some of the liquid being pumped is diverted through pipe 56 from which it ilows in high velocity streams against the sides of the screen units, serving to prevent clogging thereof. The openings 58 may be characterized as small relative to the diameter of the pipe 56 and these should be of a size such that the pressure of the liquid will cause the same to issue through the holes at high velocity. Nozzles may be used in place of the holes.

Although I have illustrated and described a preferred form of my invention, I contemplate that various changes and modifications can be made without departing from the invention, the scope of which is indicated by the following claim.

I "claim:

In apparatus of the type described including a tank and a conduit entering the tank above the bottom thereof for delivering fluid thereinto, the combination therewith of an open-topped main screening device having side walls and a bottom Wall of wire mesh, means suspending said device from the tank in position to receive' uid `delivered by said conduit, an open-topped auxiliary Screening device laterally adjacent to but spaced from Said main screening device, means suspending said auxiliary screening from said tank, said screening devices having their bottom walls spaced above the bottom of the tank, the upper end of said auxiliary screening device being at a lower elevation than the upper end of said main screening device, and apron means vextending from the '15 2,402,553

. 4 upper end of said main screening device to the upper end of said auxiliary screening device Yfor conveying overi iiow from said main screening device into said auxiliary screening device.

References Cited in the tile of this patent UNITED STATES PATENTS 493,965 Bowman i Mar. 21, 1893 1,107,100 Jones Feb. 13, 1912 1,143,985 Morris' vJune 22, 19-15 1,331,239 Cartwright Feb. 17, 1920 1,628,201 Scoville May 10, 1927 2,240,167 Adams fi- Apr. 29, 1941 Hurt et al. June 25, 1946 

